Does this sample fairly show the whole group?

Answer Key - Grade 7 Math Worksheet

Circle the best answer, or write your answer on the line.

1. 1.

   Ari measured all 10 kites, then picked the 4 kites that flew longest. A gust showed off. How far is the mean of the 4 picked from the mean of all 10?

   5.5
2. 2.

   Luz measured all 10 bus rides, then picked the 4 shortest rides. The bus did not stop for ducks. How far is the mean of the 4 picked from the mean of all 10?

   5
3. 3.

   Tala measured all 10 riders, then picked 4 cards from a shuffled set of 10. One helmet had stickers. How far is the mean of the 4 picked from the mean of all 10?

   1
4. 4.

   Picture each of the 300 students as one dot on a dot plot. A sample is the few dots picked. Pia wants to know how many hours the 300 students at Pine School sleep on school nights. Which plan gives the sample most likely to fairly show all 300?

   • Ask the 15 students who ride the early bus.
   • Ask the 15 students waiting in the front office.
   • Draw 3 names from a hat holding all 300 names.
   • Draw 15 names from a hat holding all 300 names.
5. 5.

   Picture each of the 250 books as one dot on a dot plot. A sample is the few dots picked. Milo wants to know how many pages the 250 books on the class shelves have. Which plan gives the sample most likely to fairly show all 250?

   • Draw 2 book cards from a box holding all 250 cards, then stop
   • Draw 10 book cards from a box holding all 250 cards.
   • Check the 10 books students recommend.
   • Check the 10 books on the lowest shelf.
6. 6.

   Picture each of the 140 players as one dot on a dot plot. A sample is the few dots picked. Zee wants to know how many minutes the 140 players in a soccer league practice each week. Which plan gives the sample most likely to fairly show all 140?

   • Shuffle 140 player cards and deal out 14.
   • Ask the 14 players on the top team.
   • Ask the 14 players at today's practice.
   • Shuffle 140 player cards and deal out 2, then stop there
7. 7.

   Kira measured heights in centimeters for 10 bean plants. Kira picked the 4 plants nearest the sunny window. Which statement about the sample is true?

   • It is fair, because Kira recorded each picked bean plant carefully.
   • It is fair, because every dot had the same chance of being picked.
   • It is biased, because it has fewer dots than the whole group.
   • It is biased, because the picked dots all come from one part of the plot.
8. 8.

   Esme measured minutes of reading a night for 10 numbered club members. Esme dealt 4 cards from 10 shuffled name cards. Which statement about the sample is true?

   • It is fair, because Esme recorded each picked club member carefully.
   • It is biased, because the picked dots all come from one part of the plot.
   • It is biased, because it has fewer dots than the whole group.
   • It is fair, because every dot had the same chance of being picked.
9. 9.

   Noah measured inches in a standing long jump for 10 jumpers. Noah picked the 4 jumpers on the school team. Which statement about the sample is true?

   • It is biased, because the picked dots all come from one part of the plot.
   • It is fair, because every dot had the same chance of being picked.
   • It is fair, because Noah recorded each picked jumper carefully.
   • It is biased, because it has fewer dots than the whole group.
10. 10.

    Ari measured lengths in centimeters for 10 numbered shells. Ari drew 4 numbers from a bag of 10. Which statement about the sample is true?

    • It is biased, because the picked dots all come from one part of the plot.
    • It is biased, because it has fewer dots than the whole group.
    • It is fair, because every dot had the same chance of being picked.
    • It is fair, because Ari recorded each picked shell carefully.